Integrating keystore with keyguard (Part 1 of 4)

Summary:

frameworks/base
  keystore rewrite
  keyguard integration with keystore on keyguard entry or keyguard change
  KeyStore API simplification

packages/apps/Settings
  Removed com.android.credentials.SET_PASSWORD intent support
  Added keyguard requirement for keystore use

packages/apps/CertInstaller
  Tracking KeyStore API changes
  Fix for NPE in CertInstaller when certificate lacks basic constraints

packages/apps/KeyChain
  Tracking KeyStore API changes

Details:

frameworks/base

   Move keystore from C to C++ while rewriting password
   implementation. Removed global variables. Added many comments.

	cmds/keystore/Android.mk
	cmds/keystore/keystore.h
	cmds/keystore/keystore.c => cmds/keystore/keystore.cpp
	cmds/keystore/keystore_cli.c => cmds/keystore/keystore_cli.cpp

   Changed saveLockPattern and saveLockPassword to notify the keystore
   on changes so that the keystore master key can be reencrypted when
   the keyguard changes.

	core/java/com/android/internal/widget/LockPatternUtils.java

   Changed unlock screens to pass values for keystore unlock or initialization

	policy/src/com/android/internal/policy/impl/PasswordUnlockScreen.java
	policy/src/com/android/internal/policy/impl/PatternUnlockScreen.java

   KeyStore API changes
   - renamed test() to state(), which now return a State enum
   - made APIs with byte[] key arguments private
   - added new KeyStore.isEmpty used to determine if a keyguard is required

	keystore/java/android/security/KeyStore.java

   In addition to tracking KeyStore API changes, added new testIsEmpty
   and improved some existing tests to validate expect values.

	keystore/tests/src/android/security/KeyStoreTest.java

packages/apps/Settings

    Removing com.android.credentials.SET_PASSWORD intent with the
    removal of the ability to set an explicit keystore password now
    that the keyguard value is used. Changed to ensure keyguard is
    enabled for keystore install or unlock. Cleaned up interwoven
    dialog handing into discrete dialog helper classes.

	AndroidManifest.xml
	src/com/android/settings/CredentialStorage.java

    Remove layout for entering new password

	res/layout/credentials_dialog.xml

    Remove enable credentials checkbox

	res/xml/security_settings_misc.xml
	src/com/android/settings/SecuritySettings.java

    Added ability to specify minimum quality key to ChooseLockGeneric
    Activity. Used by CredentialStorage, but could also be used by
    CryptKeeperSettings. Changed ChooseLockGeneric to understand
    minimum quality for keystore in addition to DPM and device
    encryption.

	src/com/android/settings/ChooseLockGeneric.java

    Changed to use getActivePasswordQuality from
    getKeyguardStoredPasswordQuality based on experience in
    CredentialStorage. Removed bogus class javadoc.

	src/com/android/settings/CryptKeeperSettings.java

    Tracking KeyStore API changes

	src/com/android/settings/vpn/VpnSettings.java
	src/com/android/settings/wifi/WifiSettings.java

   Removing now unused string resources

	res/values-af/strings.xml
	res/values-am/strings.xml
	res/values-ar/strings.xml
	res/values-bg/strings.xml
	res/values-ca/strings.xml
	res/values-cs/strings.xml
	res/values-da/strings.xml
	res/values-de/strings.xml
	res/values-el/strings.xml
	res/values-en-rGB/strings.xml
	res/values-es-rUS/strings.xml
	res/values-es/strings.xml
	res/values-fa/strings.xml
	res/values-fi/strings.xml
	res/values-fr/strings.xml
	res/values-hr/strings.xml
	res/values-hu/strings.xml
	res/values-in/strings.xml
	res/values-it/strings.xml
	res/values-iw/strings.xml
	res/values-ja/strings.xml
	res/values-ko/strings.xml
	res/values-lt/strings.xml
	res/values-lv/strings.xml
	res/values-ms/strings.xml
	res/values-nb/strings.xml
	res/values-nl/strings.xml
	res/values-pl/strings.xml
	res/values-pt-rPT/strings.xml
	res/values-pt/strings.xml
	res/values-rm/strings.xml
	res/values-ro/strings.xml
	res/values-ru/strings.xml
	res/values-sk/strings.xml
	res/values-sl/strings.xml
	res/values-sr/strings.xml
	res/values-sv/strings.xml
	res/values-sw/strings.xml
	res/values-th/strings.xml
	res/values-tl/strings.xml
	res/values-tr/strings.xml
	res/values-uk/strings.xml
	res/values-vi/strings.xml
	res/values-zh-rCN/strings.xml
	res/values-zh-rTW/strings.xml
	res/values-zu/strings.xml
	res/values/strings.xml

packages/apps/CertInstaller

  Tracking KeyStore API changes
	src/com/android/certinstaller/CertInstaller.java

  Fix for NPE in CertInstaller when certificate lacks basic constraints
	src/com/android/certinstaller/CredentialHelper.java

packages/apps/KeyChain

  Tracking KeyStore API changes
	src/com/android/keychain/KeyChainActivity.java
	src/com/android/keychain/KeyChainService.java
	support/src/com/android/keychain/tests/support/IKeyChainServiceTestSupport.aidl
	support/src/com/android/keychain/tests/support/KeyChainServiceTestSupport.java
	tests/src/com/android/keychain/tests/KeyChainServiceTest.java

Change-Id: Ic141fb5d4b43d12fe62cb1e29c7cbd891b4be35d

5 files changed, 851 insertions, 621 deletions

diff --git a/cmds/keystore/Android.mk b/cmds/keystore/Android.mk
index 15a199f..67dd9f8 100644
--- a/cmds/keystore/Android.mk
+++ b/cmds/keystore/Android.mk
@@ -19,14 +19,14 @@ ifneq ($(TARGET_SIMULATOR),true)
 LOCAL_PATH:= $(call my-dir)
 
 include $(CLEAR_VARS)
-LOCAL_SRC_FILES := keystore.c
+LOCAL_SRC_FILES := keystore.cpp
 LOCAL_C_INCLUDES := external/openssl/include
 LOCAL_SHARED_LIBRARIES := libcutils libcrypto
 LOCAL_MODULE:= keystore
 include $(BUILD_EXECUTABLE)
 
 include $(CLEAR_VARS)
-LOCAL_SRC_FILES := keystore_cli.c
+LOCAL_SRC_FILES := keystore_cli.cpp
 LOCAL_C_INCLUDES := external/openssl/include
 LOCAL_SHARED_LIBRARIES := libcutils libcrypto
 LOCAL_MODULE:= keystore_cli
diff --git a/cmds/keystore/keystore.c b/cmds/keystore/keystore.c
deleted file mode 100644
index e34053b..0000000
--- a/cmds/keystore/keystore.c
+++ /dev/null
@@ -1,590 +0,0 @@
-/*
- * Copyright (C) 2009 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#include <stdio.h>
-#include <stdint.h>
-#include <string.h>
-#include <unistd.h>
-#include <signal.h>
-#include <errno.h>
-#include <dirent.h>
-#include <fcntl.h>
-#include <limits.h>
-#include <sys/types.h>
-#include <sys/socket.h>
-#include <sys/stat.h>
-#include <sys/time.h>
-#include <arpa/inet.h>
-
-#include <openssl/aes.h>
-#include <openssl/evp.h>
-#include <openssl/md5.h>
-
-#define LOG_TAG "keystore"
-#include <cutils/log.h>
-#include <cutils/sockets.h>
-#include <private/android_filesystem_config.h>
-
-#include "keystore.h"
-
-/* KeyStore is a secured storage for key-value pairs. In this implementation,
- * each file stores one key-value pair. Keys are encoded in file names, and
- * values are encrypted with checksums. The encryption key is protected by a
- * user-defined password. To keep things simple, buffers are always larger than
- * the maximum space we needed, so boundary checks on buffers are omitted. */
-
-#define KEY_SIZE        ((NAME_MAX - 15) / 2)
-#define VALUE_SIZE      32768
-#define PASSWORD_SIZE   VALUE_SIZE
-
-/* Here is the encoding of keys. This is necessary in order to allow arbitrary
- * characters in keys. Characters in [0-~] are not encoded. Others are encoded
- * into two bytes. The first byte is one of [+-.] which represents the first
- * two bits of the character. The second byte encodes the rest of the bits into
- * [0-o]. Therefore in the worst case the length of a key gets doubled. Note
- * that Base64 cannot be used here due to the need of prefix match on keys. */
-
-static int encode_key(char *out, uint8_t *in, int length)
-{
-    int i;
-    for (i = length; i > 0; --i, ++in, ++out) {
-        if (*in >= '0' && *in <= '~') {
-            *out = *in;
-        } else {
-            *out = '+' + (*in >> 6);
-            *++out = '0' + (*in & 0x3F);
-            ++length;
-        }
-    }
-    *out = 0;
-    return length;
-}
-
-static int decode_key(uint8_t *out, char *in, int length)
-{
-    int i;
-    for (i = 0; i < length; ++i, ++in, ++out) {
-        if (*in >= '0' && *in <= '~') {
-            *out = *in;
-        } else {
-            *out = (*in - '+') << 6;
-            *out |= (*++in - '0') & 0x3F;
-            --length;
-        }
-    }
-    *out = 0;
-    return length;
-}
-
-/* Here is the protocol used in both requests and responses:
- *     code [length_1 message_1 ... length_n message_n] end-of-file
- * where code is one byte long and lengths are unsigned 16-bit integers in
- * network order. Thus the maximum length of a message is 65535 bytes. */
-
-static int the_socket = -1;
-
-static int recv_code(int8_t *code)
-{
-    return recv(the_socket, code, 1, 0) == 1;
-}
-
-static int recv_message(uint8_t *message, int length)
-{
-    uint8_t bytes[2];
-    if (recv(the_socket, &bytes[0], 1, 0) != 1 ||
-        recv(the_socket, &bytes[1], 1, 0) != 1) {
-        return -1;
-    } else {
-        int offset = bytes[0] << 8 | bytes[1];
-        if (length < offset) {
-            return -1;
-        }
-        length = offset;
-        offset = 0;
-        while (offset < length) {
-            int n = recv(the_socket, &message[offset], length - offset, 0);
-            if (n <= 0) {
-                return -1;
-            }
-            offset += n;
-        }
-    }
-    return length;
-}
-
-static int recv_end_of_file()
-{
-    uint8_t byte;
-    return recv(the_socket, &byte, 1, 0) == 0;
-}
-
-static void send_code(int8_t code)
-{
-    send(the_socket, &code, 1, 0);
-}
-
-static void send_message(uint8_t *message, int length)
-{
-    uint16_t bytes = htons(length);
-    send(the_socket, &bytes, 2, 0);
-    send(the_socket, message, length, 0);
-}
-
-/* Here is the file format. There are two parts in blob.value, the secret and
- * the description. The secret is stored in ciphertext, and its original size
- * can be found in blob.length. The description is stored after the secret in
- * plaintext, and its size is specified in blob.info. The total size of the two
- * parts must be no more than VALUE_SIZE bytes. The first three bytes of the
- * file are reserved for future use and are always set to zero. Fields other
- * than blob.info, blob.length, and blob.value are modified by encrypt_blob()
- * and decrypt_blob(). Thus they should not be accessed from outside. */
-
-static int the_entropy = -1;
-
-static struct __attribute__((packed)) {
-    uint8_t reserved[3];
-    uint8_t info;
-    uint8_t vector[AES_BLOCK_SIZE];
-    uint8_t encrypted[0];
-    uint8_t digest[MD5_DIGEST_LENGTH];
-    uint8_t digested[0];
-    int32_t length;
-    uint8_t value[VALUE_SIZE + AES_BLOCK_SIZE];
-} blob;
-
-static int8_t encrypt_blob(char *name, AES_KEY *aes_key)
-{
-    uint8_t vector[AES_BLOCK_SIZE];
-    int length;
-    int fd;
-
-    if (read(the_entropy, blob.vector, AES_BLOCK_SIZE) != AES_BLOCK_SIZE) {
-        return SYSTEM_ERROR;
-    }
-
-    length = blob.length + (blob.value - blob.encrypted);
-    length = (length + AES_BLOCK_SIZE - 1) / AES_BLOCK_SIZE * AES_BLOCK_SIZE;
-
-    if (blob.info != 0) {
-        memmove(&blob.encrypted[length], &blob.value[blob.length], blob.info);
-    }
-
-    blob.length = htonl(blob.length);
-    MD5(blob.digested, length - (blob.digested - blob.encrypted), blob.digest);
-
-    memcpy(vector, blob.vector, AES_BLOCK_SIZE);
-    AES_cbc_encrypt(blob.encrypted, blob.encrypted, length, aes_key, vector,
-                    AES_ENCRYPT);
-
-    memset(blob.reserved, 0, sizeof(blob.reserved));
-    length += (blob.encrypted - (uint8_t *)&blob) + blob.info;
-
-    fd = open(".tmp", O_WRONLY | O_TRUNC | O_CREAT, S_IRUSR | S_IWUSR);
-    length -= write(fd, &blob, length);
-    close(fd);
-    return (length || rename(".tmp", name)) ? SYSTEM_ERROR : NO_ERROR;
-}
-
-static int8_t decrypt_blob(char *name, AES_KEY *aes_key)
-{
-    int fd = open(name, O_RDONLY);
-    int length;
-
-    if (fd == -1) {
-        return (errno == ENOENT) ? KEY_NOT_FOUND : SYSTEM_ERROR;
-    }
-    length = read(fd, &blob, sizeof(blob));
-    close(fd);
-
-    length -= (blob.encrypted - (uint8_t *)&blob) + blob.info;
-    if (length < blob.value - blob.encrypted || length % AES_BLOCK_SIZE != 0) {
-        return VALUE_CORRUPTED;
-    }
-
-    AES_cbc_encrypt(blob.encrypted, blob.encrypted, length, aes_key,
-                    blob.vector, AES_DECRYPT);
-    length -= blob.digested - blob.encrypted;
-    if (memcmp(blob.digest, MD5(blob.digested, length, NULL),
-               MD5_DIGEST_LENGTH)) {
-        return VALUE_CORRUPTED;
-    }
-
-    length -= blob.value - blob.digested;
-    blob.length = ntohl(blob.length);
-    if (blob.length < 0 || blob.length > length) {
-        return VALUE_CORRUPTED;
-    }
-    if (blob.info != 0) {
-        memmove(&blob.value[blob.length], &blob.value[length], blob.info);
-    }
-    return NO_ERROR;
-}
-
-/* Here are the actions. Each of them is a function without arguments. All
- * information is defined in global variables, which are set properly before
- * performing an action. The number of parameters required by each action is
- * fixed and defined in a table. If the return value of an action is positive,
- * it will be treated as a response code and transmitted to the client. Note
- * that the lengths of parameters are checked when they are received, so
- * boundary checks on parameters are omitted. */
-
-#define MAX_PARAM   2
-#define MAX_RETRY   4
-
-static uid_t uid = -1;
-static int8_t state = UNINITIALIZED;
-static int8_t retry = MAX_RETRY;
-
-static struct {
-    int length;
-    uint8_t value[VALUE_SIZE];
-} params[MAX_PARAM];
-
-static AES_KEY encryption_key;
-static AES_KEY decryption_key;
-
-static int8_t test()
-{
-    return state;
-}
-
-static int8_t get()
-{
-    char name[NAME_MAX];
-    int n = sprintf(name, "%u_", uid);
-    encode_key(&name[n], params[0].value, params[0].length);
-    n = decrypt_blob(name, &decryption_key);
-    if (n != NO_ERROR) {
-        return n;
-    }
-    send_code(NO_ERROR);
-    send_message(blob.value, blob.length);
-    return -NO_ERROR;
-}
-
-static int8_t insert()
-{
-    char name[NAME_MAX];
-    int n = sprintf(name, "%u_", uid);
-    encode_key(&name[n], params[0].value, params[0].length);
-    blob.info = 0;
-    blob.length = params[1].length;
-    memcpy(blob.value, params[1].value, params[1].length);
-    return encrypt_blob(name, &encryption_key);
-}
-
-static int8_t delete()
-{
-    char name[NAME_MAX];
-    int n = sprintf(name, "%u_", uid);
-    encode_key(&name[n], params[0].value, params[0].length);
-    return (unlink(name) && errno != ENOENT) ? SYSTEM_ERROR : NO_ERROR;
-}
-
-static int8_t exist()
-{
-    char name[NAME_MAX];
-    int n = sprintf(name, "%u_", uid);
-    encode_key(&name[n], params[0].value, params[0].length);
-    if (access(name, R_OK) == -1) {
-        return (errno != ENOENT) ? SYSTEM_ERROR : KEY_NOT_FOUND;
-    }
-    return NO_ERROR;
-}
-
-static int8_t saw()
-{
-    DIR *dir = opendir(".");
-    struct dirent *file;
-    char name[NAME_MAX];
-    int n;
-
-    if (!dir) {
-        return SYSTEM_ERROR;
-    }
-    n = sprintf(name, "%u_", uid);
-    n += encode_key(&name[n], params[0].value, params[0].length);
-    send_code(NO_ERROR);
-    while ((file = readdir(dir)) != NULL) {
-        if (!strncmp(name, file->d_name, n)) {
-            char *p = &file->d_name[n];
-            params[0].length = decode_key(params[0].value, p, strlen(p));
-            send_message(params[0].value, params[0].length);
-        }
-    }
-    closedir(dir);
-    return -NO_ERROR;
-}
-
-static int8_t reset()
-{
-    DIR *dir = opendir(".");
-    struct dirent *file;
-
-    memset(&encryption_key, 0, sizeof(encryption_key));
-    memset(&decryption_key, 0, sizeof(decryption_key));
-    state = UNINITIALIZED;
-    retry = MAX_RETRY;
-
-    if (!dir) {
-        return SYSTEM_ERROR;
-    }
-    while ((file = readdir(dir)) != NULL) {
-        unlink(file->d_name);
-    }
-    closedir(dir);
-    return NO_ERROR;
-}
-
-#define MASTER_KEY_FILE ".masterkey"
-#define MASTER_KEY_SIZE 16
-#define SALT_SIZE       16
-
-static void set_key(uint8_t *key, uint8_t *password, int length, uint8_t *salt)
-{
-    if (salt) {
-        PKCS5_PBKDF2_HMAC_SHA1((char *)password, length, salt, SALT_SIZE,
-                               8192, MASTER_KEY_SIZE, key);
-    } else {
-        PKCS5_PBKDF2_HMAC_SHA1((char *)password, length, (uint8_t *)"keystore",
-                               sizeof("keystore"), 1024, MASTER_KEY_SIZE, key);
-    }
-}
-
-/* Here is the history. To improve the security, the parameters to generate the
- * master key has been changed. To make a seamless transition, we update the
- * file using the same password when the user unlock it for the first time. If
- * any thing goes wrong during the transition, the new file will not overwrite
- * the old one. This avoids permanent damages of the existing data. */
-
-static int8_t password()
-{
-    uint8_t key[MASTER_KEY_SIZE];
-    AES_KEY aes_key;
-    int8_t response = SYSTEM_ERROR;
-
-    if (state == UNINITIALIZED) {
-        if (read(the_entropy, blob.value, MASTER_KEY_SIZE) != MASTER_KEY_SIZE) {
-           return SYSTEM_ERROR;
-        }
-    } else {
-        int fd = open(MASTER_KEY_FILE, O_RDONLY);
-        uint8_t *salt = NULL;
-        if (fd != -1) {
-            int length = read(fd, &blob, sizeof(blob));
-            close(fd);
-            if (length > SALT_SIZE && blob.info == SALT_SIZE) {
-                salt = (uint8_t *)&blob + length - SALT_SIZE;
-            }
-        }
-
-        set_key(key, params[0].value, params[0].length, salt);
-        AES_set_decrypt_key(key, MASTER_KEY_SIZE * 8, &aes_key);
-        response = decrypt_blob(MASTER_KEY_FILE, &aes_key);
-        if (response == SYSTEM_ERROR) {
-            return SYSTEM_ERROR;
-        }
-        if (response != NO_ERROR || blob.length != MASTER_KEY_SIZE) {
-            if (retry <= 0) {
-                reset();
-                return UNINITIALIZED;
-            }
-            return WRONG_PASSWORD + --retry;
-        }
-
-        if (!salt && params[1].length == -1) {
-            params[1] = params[0];
-        }
-    }
-
-    if (params[1].length == -1) {
-        memcpy(key, blob.value, MASTER_KEY_SIZE);
-    } else {
-        uint8_t *salt = &blob.value[MASTER_KEY_SIZE];
-        if (read(the_entropy, salt, SALT_SIZE) != SALT_SIZE) {
-            return SYSTEM_ERROR;
-        }
-
-        set_key(key, params[1].value, params[1].length, salt);
-        AES_set_encrypt_key(key, MASTER_KEY_SIZE * 8, &aes_key);
-        memcpy(key, blob.value, MASTER_KEY_SIZE);
-        blob.info = SALT_SIZE;
-        blob.length = MASTER_KEY_SIZE;
-        response = encrypt_blob(MASTER_KEY_FILE, &aes_key);
-    }
-
-    if (response == NO_ERROR) {
-        AES_set_encrypt_key(key, MASTER_KEY_SIZE * 8, &encryption_key);
-        AES_set_decrypt_key(key, MASTER_KEY_SIZE * 8, &decryption_key);
-        state = NO_ERROR;
-        retry = MAX_RETRY;
-    }
-    return response;
-}
-
-static int8_t lock()
-{
-    memset(&encryption_key, 0, sizeof(encryption_key));
-    memset(&decryption_key, 0, sizeof(decryption_key));
-    state = LOCKED;
-    return NO_ERROR;
-}
-
-static int8_t unlock()
-{
-    params[1].length = -1;
-    return password();
-}
-
-/* Here are the permissions, actions, users, and the main function. */
-
-enum perm {
-    TEST     =   1,
-    GET      =   2,
-    INSERT   =   4,
-    DELETE   =   8,
-    EXIST    =  16,
-    SAW      =  32,
-    RESET    =  64,
-    PASSWORD = 128,
-    LOCK     = 256,
-    UNLOCK   = 512,
-};
-
-static struct action {
-    int8_t (*run)();
-    int8_t code;
-    int8_t state;
-    uint32_t perm;
-    int lengths[MAX_PARAM];
-} actions[] = {
-    {test,     't', 0,        TEST,     {0}},
-    {get,      'g', NO_ERROR, GET,      {KEY_SIZE}},
-    {insert,   'i', NO_ERROR, INSERT,   {KEY_SIZE, VALUE_SIZE}},
-    {delete,   'd', 0,        DELETE,   {KEY_SIZE}},
-    {exist,    'e', 0,        EXIST,    {KEY_SIZE}},
-    {saw,      's', 0,        SAW,      {KEY_SIZE}},
-    {reset,    'r', 0,        RESET,    {0}},
-    {password, 'p', 0,        PASSWORD, {PASSWORD_SIZE, PASSWORD_SIZE}},
-    {lock,     'l', NO_ERROR, LOCK,     {0}},
-    {unlock,   'u', LOCKED,   UNLOCK,   {PASSWORD_SIZE}},
-    {NULL,      0 , 0,        0,        {0}},
-};
-
-static struct user {
-    uid_t uid;
-    uid_t euid;
-    uint32_t perms;
-} users[] = {
-    {AID_SYSTEM,   ~0,         ~GET},
-    {AID_VPN,      AID_SYSTEM, GET},
-    {AID_WIFI,     AID_SYSTEM, GET},
-    {AID_ROOT,     AID_SYSTEM, GET},
-    {AID_KEYCHAIN, AID_SYSTEM, TEST | GET | SAW},
-    {~0,           ~0,         TEST | GET | INSERT | DELETE | EXIST | SAW},
-};
-
-static int8_t process(int8_t code) {
-    struct user *user = users;
-    struct action *action = actions;
-    int i;
-
-    while (~user->uid && user->uid != uid) {
-        ++user;
-    }
-    while (action->code && action->code != code) {
-        ++action;
-    }
-    if (!action->code) {
-        return UNDEFINED_ACTION;
-    }
-    if (!(action->perm & user->perms)) {
-        return PERMISSION_DENIED;
-    }
-    if (action->state && action->state != state) {
-        return state;
-    }
-    if (~user->euid) {
-        uid = user->euid;
-    }
-    for (i = 0; i < MAX_PARAM && action->lengths[i]; ++i) {
-        params[i].length = recv_message(params[i].value, action->lengths[i]);
-        if (params[i].length == -1) {
-            return PROTOCOL_ERROR;
-        }
-    }
-    if (!recv_end_of_file()) {
-        return PROTOCOL_ERROR;
-    }
-    return action->run();
-}
-
-#define RANDOM_DEVICE   "/dev/urandom"
-
-int main(int argc, char **argv)
-{
-    int control_socket = android_get_control_socket("keystore");
-    if (argc < 2) {
-        LOGE("A directory must be specified!");
-        return 1;
-    }
-    if (chdir(argv[1]) == -1) {
-        LOGE("chdir: %s: %s", argv[1], strerror(errno));
-        return 1;
-    }
-    if ((the_entropy = open(RANDOM_DEVICE, O_RDONLY)) == -1) {
-        LOGE("open: %s: %s", RANDOM_DEVICE, strerror(errno));
-        return 1;
-    }
-    if (listen(control_socket, 3) == -1) {
-        LOGE("listen: %s", strerror(errno));
-        return 1;
-    }
-
-    signal(SIGPIPE, SIG_IGN);
-    if (access(MASTER_KEY_FILE, R_OK) == 0) {
-        state = LOCKED;
-    }
-
-    while ((the_socket = accept(control_socket, NULL, 0)) != -1) {
-        struct timeval tv = {.tv_sec = 3};
-        struct ucred cred;
-        socklen_t size = sizeof(cred);
-        int8_t request;
-
-        setsockopt(the_socket, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv));
-        setsockopt(the_socket, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv));
-
-        if (getsockopt(the_socket, SOL_SOCKET, SO_PEERCRED, &cred, &size)) {
-            LOGW("getsockopt: %s", strerror(errno));
-        } else if (recv_code(&request)) {
-            int8_t old_state = state;
-            int8_t response;
-            uid = cred.uid;
-
-            if ((response = process(request)) > 0) {
-                send_code(response);
-                response = -response;
-            }
-
-            LOGI("uid: %d action: %c -> %d state: %d -> %d retry: %d",
-                 cred.uid, request, -response, old_state, state, retry);
-        }
-        close(the_socket);
-    }
-    LOGE("accept: %s", strerror(errno));
-    return 1;
-}
diff --git a/cmds/keystore/keystore.cpp b/cmds/keystore/keystore.cpp
new file mode 100644
index 0000000..31db9fd
--- /dev/null
+++ b/cmds/keystore/keystore.cpp
@@ -0,0 +1,812 @@
+/*
+ * Copyright (C) 2009 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <string.h>
+#include <unistd.h>
+#include <signal.h>
+#include <errno.h>
+#include <dirent.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <arpa/inet.h>
+
+#include <openssl/aes.h>
+#include <openssl/evp.h>
+#include <openssl/md5.h>
+
+#define LOG_TAG "keystore"
+#include <cutils/log.h>
+#include <cutils/sockets.h>
+#include <private/android_filesystem_config.h>
+
+#include "keystore.h"
+
+/* KeyStore is a secured storage for key-value pairs. In this implementation,
+ * each file stores one key-value pair. Keys are encoded in file names, and
+ * values are encrypted with checksums. The encryption key is protected by a
+ * user-defined password. To keep things simple, buffers are always larger than
+ * the maximum space we needed, so boundary checks on buffers are omitted. */
+
+#define KEY_SIZE        ((NAME_MAX - 15) / 2)
+#define VALUE_SIZE      32768
+#define PASSWORD_SIZE   VALUE_SIZE
+
+struct Value {
+    int length;
+    uint8_t value[VALUE_SIZE];
+};
+
+/* Here is the encoding of keys. This is necessary in order to allow arbitrary
+ * characters in keys. Characters in [0-~] are not encoded. Others are encoded
+ * into two bytes. The first byte is one of [+-.] which represents the first
+ * two bits of the character. The second byte encodes the rest of the bits into
+ * [0-o]. Therefore in the worst case the length of a key gets doubled. Note
+ * that Base64 cannot be used here due to the need of prefix match on keys. */
+
+static int encode_key(char* out, uid_t uid, const Value* key) {
+    int n = snprintf(out, NAME_MAX, "%u_", uid);
+    out += n;
+    const uint8_t* in = key->value;
+    int length = key->length;
+    for (int i = length; i > 0; --i, ++in, ++out) {
+        if (*in >= '0' && *in <= '~') {
+            *out = *in;
+        } else {
+            *out = '+' + (*in >> 6);
+            *++out = '0' + (*in & 0x3F);
+            ++length;
+        }
+    }
+    *out = '\0';
+    return n + length;
+}
+
+static int decode_key(uint8_t* out, char* in, int length) {
+    for (int i = 0; i < length; ++i, ++in, ++out) {
+        if (*in >= '0' && *in <= '~') {
+            *out = *in;
+        } else {
+            *out = (*in - '+') << 6;
+            *out |= (*++in - '0') & 0x3F;
+            --length;
+        }
+    }
+    *out = '\0';
+    return length;
+}
+
+static size_t readFully(int fd, uint8_t* data, size_t size) {
+    size_t remaining = size;
+    while (remaining > 0) {
+        ssize_t n = TEMP_FAILURE_RETRY(read(fd, data, size));
+        if (n == -1 || n == 0) {
+            return size-remaining;
+        }
+        data += n;
+        remaining -= n;
+    }
+    return size;
+}
+
+static size_t writeFully(int fd, uint8_t* data, size_t size) {
+    size_t remaining = size;
+    while (remaining > 0) {
+        ssize_t n = TEMP_FAILURE_RETRY(write(fd, data, size));
+        if (n == -1 || n == 0) {
+            return size-remaining;
+        }
+        data += n;
+        remaining -= n;
+    }
+    return size;
+}
+
+class Entropy {
+public:
+    Entropy() : mRandom(-1) {}
+    ~Entropy() {
+        if (mRandom != -1) {
+            close(mRandom);
+        }
+    }
+
+    bool open() {
+        const char* randomDevice = "/dev/urandom";
+        mRandom = ::open(randomDevice, O_RDONLY);
+        if (mRandom == -1) {
+            LOGE("open: %s: %s", randomDevice, strerror(errno));
+            return false;
+        }
+        return true;
+    }
+
+    bool generate_random_data(uint8_t* data, size_t size) {
+        return (readFully(mRandom, data, size) == size);
+    }
+
+private:
+    int mRandom;
+};
+
+/* Here is the file format. There are two parts in blob.value, the secret and
+ * the description. The secret is stored in ciphertext, and its original size
+ * can be found in blob.length. The description is stored after the secret in
+ * plaintext, and its size is specified in blob.info. The total size of the two
+ * parts must be no more than VALUE_SIZE bytes. The first three bytes of the
+ * file are reserved for future use and are always set to zero. Fields other
+ * than blob.info, blob.length, and blob.value are modified by encryptBlob()
+ * and decryptBlob(). Thus they should not be accessed from outside. */
+
+struct __attribute__((packed)) blob {
+    uint8_t reserved[3];
+    uint8_t info;
+    uint8_t vector[AES_BLOCK_SIZE];
+    uint8_t encrypted[0];
+    uint8_t digest[MD5_DIGEST_LENGTH];
+    uint8_t digested[0];
+    int32_t length; // in network byte order when encrypted
+    uint8_t value[VALUE_SIZE + AES_BLOCK_SIZE];
+};
+
+class Blob {
+public:
+    Blob(uint8_t* value, int32_t valueLength, uint8_t* info, uint8_t infoLength) {
+        mBlob.length = valueLength;
+        memcpy(mBlob.value, value, valueLength);
+
+        mBlob.info = infoLength;
+        memcpy(mBlob.value + valueLength, info, infoLength);
+    }
+
+    Blob(blob b) {
+        mBlob = b;
+    }
+
+    Blob() {}
+
+    uint8_t* getValue() {
+        return mBlob.value;
+    }
+
+    int32_t getLength() {
+        return mBlob.length;
+    }
+
+    uint8_t getInfo() {
+        return mBlob.info;
+    }
+
+    ResponseCode encryptBlob(const char* filename, AES_KEY *aes_key, Entropy* entropy) {
+        if (!entropy->generate_random_data(mBlob.vector, AES_BLOCK_SIZE)) {
+            return SYSTEM_ERROR;
+        }
+
+        // data includes the value and the value's length
+        size_t dataLength = mBlob.length + sizeof(mBlob.length);
+        // pad data to the AES_BLOCK_SIZE
+        size_t digestedLength = ((dataLength + AES_BLOCK_SIZE - 1)
+                                 / AES_BLOCK_SIZE * AES_BLOCK_SIZE);
+        // encrypted data includes the digest value
+        size_t encryptedLength = digestedLength + MD5_DIGEST_LENGTH;
+        // move info after space for padding
+        memmove(&mBlob.encrypted[encryptedLength], &mBlob.value[mBlob.length], mBlob.info);
+        // zero padding area
+        memset(mBlob.value + mBlob.length, 0, digestedLength - dataLength);
+
+        mBlob.length = htonl(mBlob.length);
+        MD5(mBlob.digested, digestedLength, mBlob.digest);
+
+        uint8_t vector[AES_BLOCK_SIZE];
+        memcpy(vector, mBlob.vector, AES_BLOCK_SIZE);
+        AES_cbc_encrypt(mBlob.encrypted, mBlob.encrypted, encryptedLength,
+                        aes_key, vector, AES_ENCRYPT);
+
+        memset(mBlob.reserved, 0, sizeof(mBlob.reserved));
+        size_t headerLength = (mBlob.encrypted - (uint8_t*) &mBlob);
+        size_t fileLength = encryptedLength + headerLength + mBlob.info;
+
+        const char* tmpFileName = ".tmp";
+        int out = open(tmpFileName, O_WRONLY | O_TRUNC | O_CREAT, S_IRUSR | S_IWUSR);
+        if (out == -1) {
+            return SYSTEM_ERROR;
+        }
+        size_t writtenBytes = writeFully(out, (uint8_t*) &mBlob, fileLength);
+        if (close(out) != 0) {
+            return SYSTEM_ERROR;
+        }
+        if (writtenBytes != fileLength) {
+            unlink(tmpFileName);
+            return SYSTEM_ERROR;
+        }
+        return (rename(tmpFileName, filename) == 0) ? NO_ERROR : SYSTEM_ERROR;
+    }
+
+    ResponseCode decryptBlob(const char* filename, AES_KEY *aes_key) {
+        int in = open(filename, O_RDONLY);
+        if (in == -1) {
+            return (errno == ENOENT) ? KEY_NOT_FOUND : SYSTEM_ERROR;
+        }
+        // fileLength may be less than sizeof(mBlob) since the in
+        // memory version has extra padding to tolerate rounding up to
+        // the AES_BLOCK_SIZE
+        size_t fileLength = readFully(in, (uint8_t*) &mBlob, sizeof(mBlob));
+        if (close(in) != 0) {
+            return SYSTEM_ERROR;
+        }
+        size_t headerLength = (mBlob.encrypted - (uint8_t*) &mBlob);
+        if (fileLength < headerLength) {
+            return VALUE_CORRUPTED;
+        }
+
+        ssize_t encryptedLength = fileLength - (headerLength + mBlob.info);
+        if (encryptedLength < 0 || encryptedLength % AES_BLOCK_SIZE != 0) {
+            return VALUE_CORRUPTED;
+        }
+        AES_cbc_encrypt(mBlob.encrypted, mBlob.encrypted, encryptedLength, aes_key,
+                        mBlob.vector, AES_DECRYPT);
+        size_t digestedLength = encryptedLength - MD5_DIGEST_LENGTH;
+        uint8_t computedDigest[MD5_DIGEST_LENGTH];
+        MD5(mBlob.digested, digestedLength, computedDigest);
+        if (memcmp(mBlob.digest, computedDigest, MD5_DIGEST_LENGTH) != 0) {
+            return VALUE_CORRUPTED;
+        }
+
+        ssize_t maxValueLength = digestedLength - sizeof(mBlob.length);
+        mBlob.length = ntohl(mBlob.length);
+        if (mBlob.length < 0 || mBlob.length > maxValueLength) {
+            return VALUE_CORRUPTED;
+        }
+        if (mBlob.info != 0) {
+            // move info from after padding to after data
+            memmove(&mBlob.value[mBlob.length], &mBlob.value[maxValueLength], mBlob.info);
+        }
+        return NO_ERROR;
+    }
+
+private:
+    struct blob mBlob;
+};
+
+class KeyStore {
+public:
+    KeyStore(Entropy* entropy) : mEntropy(entropy), mRetry(MAX_RETRY) {
+        if (access(MASTER_KEY_FILE, R_OK) == 0) {
+            setState(STATE_LOCKED);
+        } else {
+            setState(STATE_UNINITIALIZED);
+        }
+    }
+
+    State getState() {
+        return mState;
+    }
+
+    int8_t getRetry() {
+        return mRetry;
+    }
+
+    ResponseCode initialize(Value* pw) {
+        if (!generateMasterKey()) {
+            return SYSTEM_ERROR;
+        }
+        ResponseCode response = writeMasterKey(pw);
+        if (response != NO_ERROR) {
+            return response;
+        }
+        setupMasterKeys();
+        return NO_ERROR;
+    }
+
+    ResponseCode writeMasterKey(Value* pw) {
+        uint8_t passwordKey[MASTER_KEY_SIZE_BYTES];
+        generateKeyFromPassword(passwordKey, MASTER_KEY_SIZE_BYTES, pw, mSalt);
+        AES_KEY passwordAesKey;
+        AES_set_encrypt_key(passwordKey, MASTER_KEY_SIZE_BITS, &passwordAesKey);
+        Blob masterKeyBlob(mMasterKey, sizeof(mMasterKey), mSalt, sizeof(mSalt));
+        return masterKeyBlob.encryptBlob(MASTER_KEY_FILE, &passwordAesKey, mEntropy);
+    }
+
+    ResponseCode readMasterKey(Value* pw) {
+        int in = open(MASTER_KEY_FILE, O_RDONLY);
+        if (in == -1) {
+            return SYSTEM_ERROR;
+        }
+
+        // we read the raw blob to just to get the salt to generate
+        // the AES key, then we create the Blob to use with decryptBlob
+        blob rawBlob;
+        size_t length = readFully(in, (uint8_t*) &rawBlob, sizeof(rawBlob));
+        if (close(in) != 0) {
+            return SYSTEM_ERROR;
+        }
+        // find salt at EOF if present, otherwise we have an old file
+        uint8_t* salt;
+        if (length > SALT_SIZE && rawBlob.info == SALT_SIZE) {
+            salt = (uint8_t*) &rawBlob + length - SALT_SIZE;
+        } else {
+            salt = NULL;
+        }
+        uint8_t passwordKey[MASTER_KEY_SIZE_BYTES];
+        generateKeyFromPassword(passwordKey, MASTER_KEY_SIZE_BYTES, pw, salt);
+        AES_KEY passwordAesKey;
+        AES_set_decrypt_key(passwordKey, MASTER_KEY_SIZE_BITS, &passwordAesKey);
+        Blob masterKeyBlob(rawBlob);
+        ResponseCode response = masterKeyBlob.decryptBlob(MASTER_KEY_FILE, &passwordAesKey);
+        if (response == SYSTEM_ERROR) {
+            return SYSTEM_ERROR;
+        }
+        if (response == NO_ERROR && masterKeyBlob.getLength() == MASTER_KEY_SIZE_BYTES) {
+            // if salt was missing, generate one and write a new master key file with the salt.
+            if (salt == NULL) {
+                if (!generateSalt()) {
+                    return SYSTEM_ERROR;
+                }
+                response = writeMasterKey(pw);
+            }
+            if (response == NO_ERROR) {
+                setupMasterKeys();
+            }
+            return response;
+        }
+        if (mRetry <= 0) {
+            reset();
+            return UNINITIALIZED;
+        }
+        --mRetry;
+        switch (mRetry) {
+            case 0: return WRONG_PASSWORD_0;
+            case 1: return WRONG_PASSWORD_1;
+            case 2: return WRONG_PASSWORD_2;
+            case 3: return WRONG_PASSWORD_3;
+            default: return WRONG_PASSWORD_3;
+        }
+    }
+
+    bool reset() {
+        clearMasterKeys();
+        setState(STATE_UNINITIALIZED);
+
+        DIR* dir = opendir(".");
+        struct dirent* file;
+
+        if (!dir) {
+            return false;
+        }
+        while ((file = readdir(dir)) != NULL) {
+            if (isKeyFile(file->d_name)) {
+                unlink(file->d_name);
+            }
+        }
+        closedir(dir);
+        return true;
+    }
+
+    bool isEmpty() {
+        DIR* dir = opendir(".");
+        struct dirent* file;
+        if (!dir) {
+            return true;
+        }
+        bool result = true;
+        while ((file = readdir(dir)) != NULL) {
+            if (isKeyFile(file->d_name)) {
+                result = false;
+                break;
+            }
+        }
+        closedir(dir);
+        return result;
+    }
+
+    void lock() {
+        clearMasterKeys();
+        setState(STATE_LOCKED);
+    }
+
+    ResponseCode get(const char* filename, Blob* keyBlob) {
+        return keyBlob->decryptBlob(filename, &mMasterKeyDecryption);
+    }
+
+    ResponseCode put(const char* filename, Blob* keyBlob) {
+        return keyBlob->encryptBlob(filename, &mMasterKeyEncryption, mEntropy);
+    }
+
+private:
+    static const char* MASTER_KEY_FILE;
+    static const int MASTER_KEY_SIZE_BYTES = 16;
+    static const int MASTER_KEY_SIZE_BITS = MASTER_KEY_SIZE_BYTES * 8;
+
+    static const int MAX_RETRY = 4;
+    static const size_t SALT_SIZE = 16;
+
+    Entropy* mEntropy;
+
+    State mState;
+    int8_t mRetry;
+
+    uint8_t mMasterKey[MASTER_KEY_SIZE_BYTES];
+    uint8_t mSalt[SALT_SIZE];
+
+    AES_KEY mMasterKeyEncryption;
+    AES_KEY mMasterKeyDecryption;
+
+    void setState(State state) {
+        mState = state;
+        if (mState == STATE_NO_ERROR || mState == STATE_UNINITIALIZED) {
+            mRetry = MAX_RETRY;
+        }
+    }
+
+    bool generateSalt() {
+        return mEntropy->generate_random_data(mSalt, sizeof(mSalt));
+    }
+
+    bool generateMasterKey() {
+        if (!mEntropy->generate_random_data(mMasterKey, sizeof(mMasterKey))) {
+            return false;
+        }
+        if (!generateSalt()) {
+            return false;
+        }
+        return true;
+    }
+
+    void setupMasterKeys() {
+        AES_set_encrypt_key(mMasterKey, MASTER_KEY_SIZE_BITS, &mMasterKeyEncryption);
+        AES_set_decrypt_key(mMasterKey, MASTER_KEY_SIZE_BITS, &mMasterKeyDecryption);
+        setState(STATE_NO_ERROR);
+    }
+
+    void clearMasterKeys() {
+        memset(mMasterKey, 0, sizeof(mMasterKey));
+        memset(mSalt, 0, sizeof(mSalt));
+        memset(&mMasterKeyEncryption, 0, sizeof(mMasterKeyEncryption));
+        memset(&mMasterKeyDecryption, 0, sizeof(mMasterKeyDecryption));
+    }
+
+    static void generateKeyFromPassword(uint8_t* key, ssize_t keySize, Value* pw, uint8_t* salt) {
+        size_t saltSize;
+        if (salt != NULL) {
+            saltSize = SALT_SIZE;
+        } else {
+            // pre-gingerbread used this hardwired salt, readMasterKey will rewrite these when found
+            salt = (uint8_t*) "keystore";
+            // sizeof = 9, not strlen = 8
+            saltSize = sizeof("keystore");
+        }
+        PKCS5_PBKDF2_HMAC_SHA1((char*) pw->value, pw->length, salt, saltSize, 8192, keySize, key);
+    }
+
+    static bool isKeyFile(const char* filename) {
+        return ((strcmp(filename, MASTER_KEY_FILE) != 0)
+                && (strcmp(filename, ".") != 0)
+                && (strcmp(filename, "..") != 0));
+    }
+};
+
+const char* KeyStore::MASTER_KEY_FILE = ".masterkey";
+
+/* Here is the protocol used in both requests and responses:
+ *     code [length_1 message_1 ... length_n message_n] end-of-file
+ * where code is one byte long and lengths are unsigned 16-bit integers in
+ * network order. Thus the maximum length of a message is 65535 bytes. */
+
+static int recv_code(int sock, int8_t* code) {
+    return recv(sock, code, 1, 0) == 1;
+}
+
+static int recv_message(int sock, uint8_t* message, int length) {
+    uint8_t bytes[2];
+    if (recv(sock, &bytes[0], 1, 0) != 1 ||
+        recv(sock, &bytes[1], 1, 0) != 1) {
+        return -1;
+    } else {
+        int offset = bytes[0] << 8 | bytes[1];
+        if (length < offset) {
+            return -1;
+        }
+        length = offset;
+        offset = 0;
+        while (offset < length) {
+            int n = recv(sock, &message[offset], length - offset, 0);
+            if (n <= 0) {
+                return -1;
+            }
+            offset += n;
+        }
+    }
+    return length;
+}
+
+static int recv_end_of_file(int sock) {
+    uint8_t byte;
+    return recv(sock, &byte, 1, 0) == 0;
+}
+
+static void send_code(int sock, int8_t code) {
+    send(sock, &code, 1, 0);
+}
+
+static void send_message(int sock, uint8_t* message, int length) {
+    uint16_t bytes = htons(length);
+    send(sock, &bytes, 2, 0);
+    send(sock, message, length, 0);
+}
+
+/* Here are the actions. Each of them is a function without arguments. All
+ * information is defined in global variables, which are set properly before
+ * performing an action. The number of parameters required by each action is
+ * fixed and defined in a table. If the return value of an action is positive,
+ * it will be treated as a response code and transmitted to the client. Note
+ * that the lengths of parameters are checked when they are received, so
+ * boundary checks on parameters are omitted. */
+
+static const ResponseCode NO_ERROR_RESPONSE_CODE_SENT = (ResponseCode) 0;
+
+static ResponseCode test(KeyStore* keyStore, int sock, uid_t uid, Value*, Value*) {
+    return (ResponseCode) keyStore->getState();
+}
+
+static ResponseCode get(KeyStore* keyStore, int sock, uid_t uid, Value* keyName, Value*) {
+    char filename[NAME_MAX];
+    encode_key(filename, uid, keyName);
+    Blob keyBlob;
+    ResponseCode responseCode = keyStore->get(filename, &keyBlob);
+    if (responseCode != NO_ERROR) {
+        return responseCode;
+    }
+    send_code(sock, NO_ERROR);
+    send_message(sock, keyBlob.getValue(), keyBlob.getLength());
+    return NO_ERROR_RESPONSE_CODE_SENT;
+}
+
+static ResponseCode insert(KeyStore* keyStore, int sock, uid_t uid, Value* keyName, Value* val) {
+    char filename[NAME_MAX];
+    encode_key(filename, uid, keyName);
+    Blob keyBlob(val->value, val->length, 0, NULL);
+    return keyStore->put(filename, &keyBlob);
+}
+
+static ResponseCode del(KeyStore* keyStore, int sock, uid_t uid, Value* keyName, Value*) {
+    char filename[NAME_MAX];
+    encode_key(filename, uid, keyName);
+    return (unlink(filename) && errno != ENOENT) ? SYSTEM_ERROR : NO_ERROR;
+}
+
+static ResponseCode exist(KeyStore* keyStore, int sock, uid_t uid, Value* keyName, Value*) {
+    char filename[NAME_MAX];
+    encode_key(filename, uid, keyName);
+    if (access(filename, R_OK) == -1) {
+        return (errno != ENOENT) ? SYSTEM_ERROR : KEY_NOT_FOUND;
+    }
+    return NO_ERROR;
+}
+
+static ResponseCode saw(KeyStore* keyStore, int sock, uid_t uid, Value* keyPrefix, Value*) {
+    DIR* dir = opendir(".");
+    if (!dir) {
+        return SYSTEM_ERROR;
+    }
+    char filename[NAME_MAX];
+    int n = encode_key(filename, uid, keyPrefix);
+    send_code(sock, NO_ERROR);
+
+    struct dirent* file;
+    while ((file = readdir(dir)) != NULL) {
+        if (!strncmp(filename, file->d_name, n)) {
+            char* p = &file->d_name[n];
+            keyPrefix->length = decode_key(keyPrefix->value, p, strlen(p));
+            send_message(sock, keyPrefix->value, keyPrefix->length);
+        }
+    }
+    closedir(dir);
+    return NO_ERROR_RESPONSE_CODE_SENT;
+}
+
+static ResponseCode reset(KeyStore* keyStore, int sock, uid_t uid, Value*, Value*) {
+    return keyStore->reset() ? NO_ERROR : SYSTEM_ERROR;
+}
+
+/* Here is the history. To improve the security, the parameters to generate the
+ * master key has been changed. To make a seamless transition, we update the
+ * file using the same password when the user unlock it for the first time. If
+ * any thing goes wrong during the transition, the new file will not overwrite
+ * the old one. This avoids permanent damages of the existing data. */
+
+static ResponseCode password(KeyStore* keyStore, int sock, uid_t uid, Value* pw, Value*) {
+    switch (keyStore->getState()) {
+        case STATE_UNINITIALIZED: {
+            // generate master key, encrypt with password, write to file, initialize mMasterKey*.
+            return keyStore->initialize(pw);
+        }
+        case STATE_NO_ERROR: {
+            // rewrite master key with new password.
+            return keyStore->writeMasterKey(pw);
+        }
+        case STATE_LOCKED: {
+            // read master key, decrypt with password, initialize mMasterKey*.
+            return keyStore->readMasterKey(pw);
+        }
+    }
+    return SYSTEM_ERROR;
+}
+
+static ResponseCode lock(KeyStore* keyStore, int sock, uid_t uid, Value*, Value*) {
+    keyStore->lock();
+    return NO_ERROR;
+}
+
+static ResponseCode unlock(KeyStore* keyStore, int sock, uid_t uid, Value* pw, Value* unused) {
+    return password(keyStore, sock, uid, pw, unused);
+}
+
+static ResponseCode zero(KeyStore* keyStore, int sock, uid_t uid, Value*, Value*) {
+    return keyStore->isEmpty() ? KEY_NOT_FOUND : NO_ERROR;
+}
+
+/* Here are the permissions, actions, users, and the main function. */
+
+enum perm {
+    TEST     =    1,
+    GET      =    2,
+    INSERT   =    4,
+    DELETE   =    8,
+    EXIST    =   16,
+    SAW      =   32,
+    RESET    =   64,
+    PASSWORD =  128,
+    LOCK     =  256,
+    UNLOCK   =  512,
+    ZERO     = 1024,
+};
+
+static const int MAX_PARAM = 2;
+
+static const State STATE_ANY = (State) 0;
+
+static struct action {
+    ResponseCode (*run)(KeyStore* keyStore, int sock, uid_t uid, Value* param1, Value* param2);
+    int8_t code;
+    State state;
+    uint32_t perm;
+    int lengths[MAX_PARAM];
+} actions[] = {
+    {test,     't', STATE_ANY,      TEST,     {0, 0}},
+    {get,      'g', STATE_NO_ERROR, GET,      {KEY_SIZE, 0}},
+    {insert,   'i', STATE_NO_ERROR, INSERT,   {KEY_SIZE, VALUE_SIZE}},
+    {del,      'd', STATE_ANY,      DELETE,   {KEY_SIZE, 0}},
+    {exist,    'e', STATE_ANY,      EXIST,    {KEY_SIZE, 0}},
+    {saw,      's', STATE_ANY,      SAW,      {KEY_SIZE, 0}},
+    {reset,    'r', STATE_ANY,      RESET,    {0, 0}},
+    {password, 'p', STATE_ANY,      PASSWORD, {PASSWORD_SIZE, 0}},
+    {lock,     'l', STATE_NO_ERROR, LOCK,     {0, 0}},
+    {unlock,   'u', STATE_LOCKED,   UNLOCK,   {PASSWORD_SIZE, 0}},
+    {zero,     'z', STATE_ANY,      ZERO,     {0, 0}},
+    {NULL,      0 , STATE_ANY,      0,        {0, 0}},
+};
+
+static struct user {
+    uid_t uid;
+    uid_t euid;
+    uint32_t perms;
+} users[] = {
+    {AID_SYSTEM,   ~0,         ~GET},
+    {AID_VPN,      AID_SYSTEM, GET},
+    {AID_WIFI,     AID_SYSTEM, GET},
+    {AID_ROOT,     AID_SYSTEM, GET},
+    {AID_KEYCHAIN, AID_SYSTEM, TEST | GET | SAW},
+    {~0,           ~0,         TEST | GET | INSERT | DELETE | EXIST | SAW},
+};
+
+static ResponseCode process(KeyStore* keyStore, int sock, uid_t uid, int8_t code) {
+    struct user* user = users;
+    struct action* action = actions;
+    int i;
+
+    while (~user->uid && user->uid != uid) {
+        ++user;
+    }
+    while (action->code && action->code != code) {
+        ++action;
+    }
+    if (!action->code) {
+        return UNDEFINED_ACTION;
+    }
+    if (!(action->perm & user->perms)) {
+        return PERMISSION_DENIED;
+    }
+    if (action->state != STATE_ANY && action->state != keyStore->getState()) {
+        return (ResponseCode) keyStore->getState();
+    }
+    if (~user->euid) {
+        uid = user->euid;
+    }
+    Value params[MAX_PARAM];
+    for (i = 0; i < MAX_PARAM && action->lengths[i] != 0; ++i) {
+        params[i].length = recv_message(sock, params[i].value, action->lengths[i]);
+        if (params[i].length < 0) {
+            return PROTOCOL_ERROR;
+        }
+    }
+    if (!recv_end_of_file(sock)) {
+        return PROTOCOL_ERROR;
+    }
+    return action->run(keyStore, sock, uid, &params[0], &params[1]);
+}
+
+int main(int argc, char* argv[]) {
+    int controlSocket = android_get_control_socket("keystore");
+    if (argc < 2) {
+        LOGE("A directory must be specified!");
+        return 1;
+    }
+    if (chdir(argv[1]) == -1) {
+        LOGE("chdir: %s: %s", argv[1], strerror(errno));
+        return 1;
+    }
+
+    Entropy entropy;
+    if (!entropy.open()) {
+        return 1;
+    }
+    if (listen(controlSocket, 3) == -1) {
+        LOGE("listen: %s", strerror(errno));
+        return 1;
+    }
+
+    signal(SIGPIPE, SIG_IGN);
+
+    KeyStore keyStore(&entropy);
+    int sock;
+    while ((sock = accept(controlSocket, NULL, 0)) != -1) {
+        struct timeval tv;
+        tv.tv_sec = 3;
+        setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv));
+        setsockopt(sock, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv));
+
+        struct ucred cred;
+        socklen_t size = sizeof(cred);
+        int credResult = getsockopt(sock, SOL_SOCKET, SO_PEERCRED, &cred, &size);
+        if (credResult != 0) {
+            LOGW("getsockopt: %s", strerror(errno));
+        } else {
+            int8_t request;
+            if (recv_code(sock, &request)) {
+                State old_state = keyStore.getState();
+                ResponseCode response = process(&keyStore, sock, cred.uid, request);
+                if (response == NO_ERROR_RESPONSE_CODE_SENT) {
+                    response = NO_ERROR;
+                } else {
+                    send_code(sock, response);
+                }
+                LOGI("uid: %d action: %c -> %d state: %d -> %d retry: %d",
+                     cred.uid,
+                     request, response,
+                     old_state, keyStore.getState(),
+                     keyStore.getRetry());
+            }
+        }
+        close(sock);
+    }
+    LOGE("accept: %s", strerror(errno));
+    return 1;
+}
diff --git a/cmds/keystore/keystore.h b/cmds/keystore/keystore.h
index 5ef51e9..5ae3d24 100644
--- a/cmds/keystore/keystore.h
+++ b/cmds/keystore/keystore.h
@@ -17,17 +17,27 @@
 #ifndef __KEYSTORE_H__
 #define __KEYSTORE_H__
 
-enum response_code {
-    NO_ERROR          =  1,
-    LOCKED            =  2,
-    UNINITIALIZED     =  3,
+// note state values overlap with ResponseCode for the purposes of the state() API
+enum State {
+    STATE_NO_ERROR      = 1,
+    STATE_LOCKED        = 2,
+    STATE_UNINITIALIZED = 3,
+};
+
+enum ResponseCode {
+    NO_ERROR          =  STATE_NO_ERROR, // 1
+    LOCKED            =  STATE_LOCKED, // 2
+    UNINITIALIZED     =  STATE_UNINITIALIZED, // 3
     SYSTEM_ERROR      =  4,
     PROTOCOL_ERROR    =  5,
     PERMISSION_DENIED =  6,
     KEY_NOT_FOUND     =  7,
     VALUE_CORRUPTED   =  8,
     UNDEFINED_ACTION  =  9,
-    WRONG_PASSWORD    = 10,
+    WRONG_PASSWORD_0  = 10,
+    WRONG_PASSWORD_1  = 11,
+    WRONG_PASSWORD_2  = 12,
+    WRONG_PASSWORD_3  = 13, // MAX_RETRY = 4
 };
 
 #endif
diff --git a/cmds/keystore/keystore_cli.c b/cmds/keystore/keystore_cli.cpp
index e8afb5a..dcd3bcb 100644
--- a/cmds/keystore/keystore_cli.c
+++ b/cmds/keystore/keystore_cli.cpp
@@ -24,44 +24,40 @@
 
 #include "keystore.h"
 
-char *responses[256] = {
-    [NO_ERROR]           = "No error",
-    [LOCKED]             = "Locked",
-    [UNINITIALIZED]      = "Uninitialized",
-    [SYSTEM_ERROR]       = "System error",
-    [PROTOCOL_ERROR]     = "Protocol error",
-    [PERMISSION_DENIED]  = "Permission denied",
-    [KEY_NOT_FOUND]      = "Key not found",
-    [VALUE_CORRUPTED]    = "Value corrupted",
-    [UNDEFINED_ACTION]   = "Undefined action",
-    [WRONG_PASSWORD]     = "Wrong password (last chance)",
-    [WRONG_PASSWORD + 1] = "Wrong password (2 tries left)",
-    [WRONG_PASSWORD + 2] = "Wrong password (3 tries left)",
-    [WRONG_PASSWORD + 3] = "Wrong password (4 tries left)",
+static const char* responses[] = {
+    NULL,
+    /* [NO_ERROR]           = */ "No error",
+    /* [LOCKED]             = */ "Locked",
+    /* [UNINITIALIZED]      = */ "Uninitialized",
+    /* [SYSTEM_ERROR]       = */ "System error",
+    /* [PROTOCOL_ERROR]     = */ "Protocol error",
+    /* [PERMISSION_DENIED]  = */ "Permission denied",
+    /* [KEY_NOT_FOUND]      = */ "Key not found",
+    /* [VALUE_CORRUPTED]    = */ "Value corrupted",
+    /* [UNDEFINED_ACTION]   = */ "Undefined action",
+    /* [WRONG_PASSWORD]     = */ "Wrong password (last chance)",
+    /* [WRONG_PASSWORD + 1] = */ "Wrong password (2 tries left)",
+    /* [WRONG_PASSWORD + 2] = */ "Wrong password (3 tries left)",
+    /* [WRONG_PASSWORD + 3] = */ "Wrong password (4 tries left)",
 };
 
-#define MAX_RESPONSE (WRONG_PASSWORD + 3)
-
-int main(int argc, char **argv)
+int main(int argc, char* argv[])
 {
-    uint8_t bytes[65536];
-    uint8_t code;
-    int sock, i;
-
     if (argc < 2) {
         printf("Usage: %s action [parameter ...]\n", argv[0]);
         return 0;
     }
 
-    sock = socket_local_client("keystore", ANDROID_SOCKET_NAMESPACE_RESERVED,
-                               SOCK_STREAM);
+    int sock = socket_local_client("keystore", ANDROID_SOCKET_NAMESPACE_RESERVED,
+                                   SOCK_STREAM);
     if (sock == -1) {
         puts("Failed to connect");
         return 1;
     }
 
     send(sock, argv[1], 1, 0);
-    for (i = 2; i < argc; ++i) {
+    uint8_t bytes[65536];
+    for (int i = 2; i < argc; ++i) {
         uint16_t length = strlen(argv[i]);
         bytes[0] = length >> 8;
         bytes[1] = length;
@@ -70,11 +66,13 @@ int main(int argc, char **argv)
     }
     shutdown(sock, SHUT_WR);
 
+    uint8_t code;
     if (recv(sock, &code, 1, 0) != 1) {
         puts("Failed to receive");
         return 1;
     }
     printf("%d %s\n", code , responses[code] ? responses[code] : "Unknown");
+    int i;
     while ((i = recv(sock, &bytes[0], 1, 0)) == 1) {
         int length;
         int offset;